1. Field of the Invention
This invention relates to a method for reducing power consumption in a liquid-cooled type rotary compressor.
2. Description of the Prior Art
In all present day liquid-cooled type rotary compressors, the gas-liquid mixture delivered out of the compression chambers has been fed directly to a liquid separating tank, a compressed gas tank or a compressed gas and liquid tank without separating the liquid from the gas during ordinary compression operation. That is to say, little attention has been given to the difference in characteristics between gas and liquid and of the effects therebetween. The characteristics of gases and liquids, however, are totally different from each other even though both are fluids. Firstly, as gas is compressible and generates compressive heat when compressed, while a liquid is incompressible. Thus, if the compression chamber is completely filled with liquid, the rotary compressor may cause stopping or may be damaged because of liquid-lock trouble. The compressor is also forced to do excessive work resulting in extra power consumption. Secondly, the viscosity of a liquid is several thousand times that of a gas, so that flow resistance of liquids and gases are very much different from each other. Therefore, it is difficult to determine the structure and dimension of conduits or pipe lines in which the mixing ratio is not uniform, which results in low efficiency compressor design based on imaginary conditions. Thirdly, since the specific gravity of liquids is several times that of gases, a liquid and a gas can easily be separated from each other by gravitation and exhibit different behaviors, so that liquid-hammering phenomenon or gas-choke phenomenon often occurs in conduits.
Thus, even persons inexperienced in hydrodynamics will realize that it is extremely difficult to deal reasonably with both fluids under a mixed condition.